Loud-speaking-telefhone receiver



E. H. ROLLINSON LOUD SPEAKING TELEPHONE RECEIVER Sept. 21,1926. 1,600,778

Filed D60. 15, 1923 v nix/c am A TTO RIVEY.

Patented Se t. 21, 1926.

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:In the-recent rapid development of radiotelephony, there hasbeen a tendency to very materially increase the power ottransmission, and also the power utilized for sound amplification, with result that. the receiner diaphrag-zrn being usually of. very thin sheet steel or iron, is of insufficient bulk and thickness to carry the correspondingly increased magnetie flux without the accent 10 panying increasein ampiitude of vibration. It made thicker. and heavier to withstand the increased magnetic pul-], .the attendant stiffness of theidiaphragm, will only impair. the clarity of transmission. Since clearness. 1!! is as essential as loudness in good transnnsa diaphragm of either metallic or non-metailic material and of very much increased .di-

ameter, and mounting at the center thereof a :separateand --distinct armatureot a diametcrcorresponding closelyto that of the usual standard receiver. -This, armature may be wh-at is termed the floating type, or

it may have its periphery supported some- What after the manner of the usualdiaphragm. It is, however, an'armature and not a diaphragm, and its sole function isto transmit-the successivempulses due to the undulating magnetic flux in the receiver magnet system to; the true diaphragm.

Inthe accompanying drawing forming a part hereof, the improvement is, shown as adapted for use in connection-,with an amplitying horn, and ,perirnanently mounted in v a supporting base.. However, thismethod of mounting is illustrative; only, since the ,-re-

ceiver may be provided with v the .nsual de vices used 'in' forming thev well-known head sets Y a r f I 'Fig. a-section of'so much otthe re-. c'eiver andits -.supportingbase as is necessary to understand the-improvement. H

- Fig.- 2 is-a similarsection detached ,from the base, and showing the armature assupported upon the-rim of the receiver cup- Fig, adetached edge view of the form of connected armature and diaphragm shown in Fig. 1. r

Fig. 4 is an under plan of the same.

coupling and rivet ,11, is the disk Figs. .5 and 6 are views similar to those of Figs. and 4, but showing the form of armature used when it is intended to be supported upon the rim of the receiver cup.

The receiver is shown as mounted in a supporting base 1, which :is of molded bakelite or :condens'ite, or it may be of anysuitablematerial .tor the purpose. flat, inverted dish-shaped ring, having a screwthreaded aperture in its upper face, to receive the extended skirt :or flange of the It is a broad I receiver cap within; which the usual receiver cup 3, with itsm agnet system .4 .is located, as shown. ,7 1

In order to. provide for the venlarged .dia-

phragni as hereinafter described, an ex- 1 tension ring 5: 1s. utilized, said ring. beln g both externally and internally threaded to screw into the internally threaded cap.v flange and toreceive the upper-threaded. portionot thereceiver cup.

Th with an internally threaded. and flanged.

aperture 6, into which the thimble 17. of, an

amplifying horn may be, screwedhjfWi-thin the cap 2, and between its lower faceoand themargin of the ring 5 are'two gaskets 58,,

9, between which amargin of the diaphragm 1 0 is held, the ring. being firmlyscrewed up,

so as to firmly clamp the diaphragm withintliecap. Suspended from the center of the diaphragm 10 to which it is securedby the I p I armature 12, which is made much thickerrandheavier than theusuaijdiaphragm, in order to carry e upper part-of the cap2fis provided;

the increased magnetic flux of the high powered. :instruments'now in common use in radio-telephony. It 1 will be; noted that e the margin of the armature 12 is free from contactwith the upper edge of the cup 3, and. it is what may be termed a floating arma-- ture. In some cases, it maybemade of considerably smaller diameter, so that its margin willcomewell within the top ofthe receiver cup. The cup 3isscrewed into the ring 5, and adjusted to bring the poles of the magnet 51- in proper relation tothe under face jot the armature, or ;to the pointwhere the greatest vibration of the diaphragmand armature will not cause contact magnet poles. 1 The circuit leads 13 from the receiver cup are carried out through the aperture 14 in the margin of the base 1, and connected to the receiving set in the usual manner.

' As thus far described, it will be noted thatwith, the

' fication of the 'device.

" The diaphragm the diaphragm 10 and its armature 12 are entirely independent and out of contact with cessive magnetic flux as is now so common.'

In Figs. 2, 5 and 6, is shown a slight modi- In this case, the cap 2 and ring 5 are the same as above described.

and armature 12 are connected by the coupling rivet 11. The rec'eiver cup 3 has at its upper margin a small annular cusp 16 upon which the margin of apertures are merely weakened supports for the armature 1'2 rests, so that when in place the diaphragm bears upon the gasket 8, against which it is held by the armature 12 through the coupling rivet 11. The armature 12 is providedwith a series of aper tures '17 annularly arranged, as'shown, so as to weaken the armature between its center and circumference, and thereby increase its flexibility. V

Many non-metallic substances are well adapted for use as diaphragms in sound receiving or reproducing devices; among these may be mentioned the following: mica, celluloid, parchmenuparchment paper, glass, insulating fiber, vulcanized rubber, etc.

The use of the armature as above described, enables use to be made of any of these substances, for it must be understood that the armature serves only as an armature and not as a sound reproducer,'its vibrations due to the undulating magnetic flux from the magnet being transmitted to the true sounddiaphragin. I

The structure as described also enables the use ofdiaphragms of very much larger diameter, and consequently of correspondingly increased vibrational amplitude. In each of the forms shown, the armature mayv be termed a floating armature, the first form properly so, and the second form because of the fact that the armature proper may be considered as that portion of the disk 12 that is within the ring of apertures 17 and the "connecting bridges between adjacent the structure and to keep the armature in place. Minor changes coin'ingwithin thespirit and scope of the invention are contemplated in the claims hereto appended, and said claims are intended tobroadly cover a receiver wherein the sound reproducing diaphragm is actuated by a floating armature connected thereto at its center.

' Another advantage for the device may be mentioned, in that the movements of the armature are communicated to the diawith the armature-diaphragm, where the magnetic pull is spread over a surface equal to that included between the magnet poles. The resulting tones coming from a diaphragm actuated from its center are found to bemucli clearer in tone, and without the muflied'sounds so frequently heard in radiotelephones.

' I claim 1. In a loud speaking telephone receiver, the combination of a receiver cap, a nonmetallic diaphragm within said cap, a floating armature secured in spaced relation to the center of said diaphragm, a screw threaded ring to clamp said diaphragm in the cap and a receiver cup having a magnet'systein andbeing adjustably secured to said ring whereby its magnet systemmay beadjust ably spaced from said armature.

'2. In a loud speaking telephone receiver, the combination of a receiver cap, a sup-' base to which said cap is rigidly" porting secured, an extension ring detachably secured within said cap, a diaphragm located within said cap, an armature spaced from and centrally secured to said diaphragm, and a receiver cup and magnet system ad'- justably screw with the poles of said magnet system spaced from said armature.

3. In a loud speaking telephone receiver, the combination of a receiver cap, a sup-' porting base therefor, an extension ring detachably secured within said cap, "a diaphragm located within and spaced'away from said cap, a floating armature centrally secured to and spaced from said diaphragm, a'recei'ver cup and its magnet sys-' tem, and means for'adjustably securing said cup within said ring with the poles of its 41-..A loud speaking telephone receiver comprising'a, receiver cup, a cap fitted therethreaded within said ring phragm at its center, and not as is the case to, said cap having an annular recess-,a pair of gaskets disposed in the reces's,a' disc diaphragm held at its edges between said gaskets, a ring screw-threaded into the recess to clamp-said gaskets and diaphragm in firm engagement in said cap-,"a metallic'armature disc rigidly held in spaced relation from said diaphragm, a. single axial connection be tween said diaphragm and armature, said armature being otherwise unconfined, a pair of magnets, and a cup in which said magnets are fixed, said magnet cup being adjustably screw-threaded into said'clamp ring.

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